Encapsulating resins having excellent transparency and heat resistance are demanded for LED devices. Epoxy resins may be subject to discoloration upon long duration of use at high temperatures, or the brightness of the light-emitting diodes may be lowered in some cases.
In addition, polyaluminosiloxanes are polymers obtained by reacting a polysiloxane and an aluminum compound and have excellent heat resistance; therefore, the polyaluminosiloxanes are used in various applications, including, for example, coating agents, sealing agents, adhesives, and the like.
For example, Japanese Patent Laid-Open Nos. Hei 9-48787 and 2003-165841 describe various aluminosiloxanes and polyaluminosiloxanes. However, there are some disadvantages that the adhesion to LED devices and molding processability still have rooms for improvement.